The presence of sulfur-containing pollutants in effluent or wastewater solutions and gaseous emissions creates disposal problems for many industries. For example, problems with sulfate, sulfite and thiosulfate range from sewers to the eutrophication of water bodies, silting and acidification. One type of effluent in which sulfur-containing pollutants such as sulfite are present is the washwater from flue gas treatment plants. The flue gases from power stations, waste incinerators and the like create severe pollution and environmental damage due to the presence of sulfur dioxide and the associated low pH. Many industries, such as printing, mining, paper, rubber, leather and petrochemical industries produce effluent waters with high sulfur-containing pollutant concentrations.
Conventional biological treatment of sulfate, sulfite and other sulfur compounds, including effluents from gas desulfurization plants, involves reduction in an anaerobic step to produce sulfide, which in turn can be biologically oxidized to elemental sulfur. When the effluent contains little organic matter, electron donors must be added in order to provide sufficient reduction equivalents for the sulfate-reducing bacteria. Electron donors include alcohols such as methanol and ethanol, carbohydrates such as glucose and other saccharides, organic acids such as acetic, propionic, butyric and lactic acid, hydrogen and carbon monoxide.
The bioremediation of various pollutants using butane-utilizing bacteria is disclosed in U.S. Pat. Nos. 5,888,396, 6,051,130, 6,110,372, 6,156,203, 6,210,579, 6,244,346 and 6,245,235, which are incorporated herein by reference.